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<blockquote data-quote="WayneF" data-source="post: 113394" data-attributes="member: 12496">The last sentence is very correct, two very different metering systems. You also get TTL BL in Center Metering mode.&nbsp; Only Spot metering switches to TTL.&nbsp; Some flashes (SB-700, SB-400, internal flash, and commander/remote flashes) can only select TTL BL mode (except Spot metering of course).&nbsp; The Exif shows this flash mode, if you have a reader that will access it (not Adobe, but the standalones, like PhotoME).&nbsp;But the TTL flash metering is always in a central zone, it seems not to move.&nbsp; Metering in Matrix mode, yes, the focus spot is dominant to metering ambient, regardless where it is moved, ambient metering goes with it.&nbsp; &nbsp; But in any mode, TTL flash always meters a central zone, my notion is it is intermediate in size between Spot and Center metering, regardless of mode.I try it this way:&nbsp; Put a large dark or black area in the center of a huge white or light frame area.&nbsp; Adjust focus sensor well off the left side (on white), or well off the right side (on white), vs. in the center (on black).&nbsp; With an ambient level that is negligible to the flash exposure.There wont be any difference in the flash picture where the focus sensor is, if the same black area&nbsp; remains in the frame center (assuming ambient is low and direct flash distance and focus is kept the same distance, for TTL BL D-lens).</blockquote>

[QUOTE="WayneF, post: 113394, member: 12496"] The last sentence is very correct, two very different metering systems. You also get TTL BL in Center Metering mode. Only Spot metering switches to TTL. Some flashes (SB-700, SB-400, internal flash, and commander/remote flashes) can only select TTL BL mode (except Spot metering of course). The Exif shows this flash mode, if you have a reader that will access it (not Adobe, but the standalones, like PhotoME). But the TTL flash metering is always in a central zone, it seems not to move. Metering in Matrix mode, yes, the focus spot is dominant to metering ambient, regardless where it is moved, ambient metering goes with it. But in any mode, TTL flash always meters a central zone, my notion is it is intermediate in size between Spot and Center metering, regardless of mode. I try it this way: Put a large dark or black area in the center of a huge white or light frame area. Adjust focus sensor well off the left side (on white), or well off the right side (on white), vs. in the center (on black). With an ambient level that is negligible to the flash exposure. There wont be any difference in the flash picture where the focus sensor is, if the same black area remains in the frame center (assuming ambient is low and direct flash distance and focus is kept the same distance, for TTL BL D-lens). [/QUOTE]

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